My neighbor, and good friend (he's not mad at me), says he can hear my code
transmissions on all the phones in his house, including the cordless ones.
No one in my house, on the other hand, can ever hear my transmissions. I
have my phones on a traditional phone line while my neighbor gets his phone
service through his television (buried coax) cable.... Any ideas?

My recollection is that cable-TV-based phone service is usually
implemented via digital cable techniques (voice-over-IP or something
similar). It becomes analog when it reaches the house (at the
cablemodem or MPOE) and is distributed over the house telephone wiring
from there.

So, the interference is probably not on the cable side itself.

There might be a couple of ways that the audio could be showing up in
his phones:

- Fundamental overload - each individual phone is reacting to the
high RF voltage levels, and is detecting the RF into audio directly.

- Interface problem - the RF is being detected into audio at one
vulnerable location, and the resulting audio is being distributed
on the phone wiring along with the normal audio of the phone
conversation.

Since your neighbor reports that it's occurring on all of the phones
(including the wireless) I tend to suspect the latter. I'd suspect
the cable-company-provided phone interface... it's probably picking up
the RF floating around on the in-house phone wiring and rectifying it
in its analog electronics.

The remedy I'd suggest is the usual one for telephone RFI - start
adding ferrites and other interference suppressors. I'd probably
start out with a bunch of the little RJ-11 plug-in RFI filters (sold
for this purpose, and also to keep DSL signals out of peoples'
phones). Start by installing one where the house phone line connects
to the cable interface. I'd also suggest getting a ferrite split core
or toroid, and winding the phone wire through it a half-dozen times as
close to the cable interface as possible.

Also, add a ferrite to the cable interface's power supply wire (again,
as close to the interface as possible) and clamp one or more ferrites
onto the TV cable itself.

By keeping your RF out of the cable/phone interface I have a feeling
that you'll probably reduce the problem quite a lot and may eliminate
it entirely.

Adding additional plug-in RFI suppressors and/or ferrite cores to the
wires on the other phones in the household may also help.

None of this is actually your responsibility, assuming that you're
transmitting legally within your privileges, but providing good advice
(and maybe a handful of plugins and ferrites) could be a helpful
gesture!

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!